Indeed, here is a short guide to help you figure out who is who in the wasteland:
bald - PKs (they want to look menacing)
longhair - madmaxes (they want to look cool)
default - pvp apes (they don't care about the look)
Important note: PKs might wear longhair to trick you ("hey, let's hunt scorpions together")
And of course, there are exceptions to these "guidelines". My slaver is bald, all my PvP characters have long hair except the female ones, and my idlers have long hair too. Oh, and another rule is never trust someone with a non-default character skin.
